A main cause of hair loss is a genetic factor. However, recently, people suffering from hair loss have gradually increased due to environmental pollution, westernized dietary habits such as processed foods, frequent perming and dyeing, bad scalp care, etc., in addition to an increase in social stress.
Hair is maintained by repeating hair growth and hair loss in a cycle of anagen, catagen and telogen. Specifically, the cycle may be divided into the anagen in which hair grows, the catagen in which growth is completed and a hair bulb part is reduced, the telogen in which papilla stops an activity and hair is maintained on the scalp, and a development stage in which the papilla starts the activity or generates new hair to replace old hair.
A period of the anagen of hair is about three to five years for a man, and four to six years for a woman, and a period of the catagen is about 30 to 45 days, and a period of the telogen is about three to four months, and accordingly, hair loss is naturally caused. In addition, at the end of the telogen, the development stage that new hair is generated starts.
The hair loss is a normal phenomenon. However normal people have a large number of hairs in an anagen state, and on the contrary, people with alopecia have a large number of hairs in the telogen state, such that a hair loss phenomenon is visually noticeable.
People with alopecia are characterized by miniaturization of hair. As hair loss proceeds, a period of the anagen is reduced, and accordingly, the miniaturization of hair also proceeds. Therefore, in order to treat hair loss, it is important to induce hair follicles from the telogen into the anagen quickly, and to increase shorten anagen.
Male pattern alopecia is a phenomenon caused by the male hormone called testosterone which is a hormone that shows male sexual characteristics and helps with the development of muscle, development of male organs, etc., in adolescence. When this testosterone is changed into stronger dihydrotestosterone (DHT) by 5 α-reductase, this hormone acts on the hair follicles by inducing the hair follicles from the anagen into the catagen, such that hair loss is caused. Therefore, in order to treat alopecia caused by the above reason, a method of inhibiting production of DHT by 5 α-reductase is mainly used.
Female pattern alopecia is mainly caused by reduction of an amount of estrogen after menopause. In the female pattern alopecia, hair loss does not occur in a front part of a head, but mainly occurs in a middle part of a head, which is unlike the male pattern alopecia. An effect of 5 α-reductase on the female pattern alopecia is smaller than that on the male pattern alopecia. Therefore, drugs inhibiting 5 α-reductase are not significantly effective for women with alopecia after menopause. Accordingly, minoxidil or estrogen is primarily used as therapeutic agents for alopecia.
Alopecia areata is caused by autoimmune diseases, mental stress, or genetic predisposition. The alopecia areata includes circular or ovoid hair loss and ringworm or trichotillomania. A cause of the alopecia areata is fundamentally different from that of androgenetic alopecia, and a treatment method thereof is also different from that of androgenetic alopecia, and accordingly, a method of treating adrenocortical hormone is used, or a method of applying minoxidil to an affected area or artificially causing stimulation to the affected area is used.
With regard to various and complex causes of hair loss as described above, currently known hair loss prevention products including components that aim at promoting blood circulation, inhibiting male hormone action, enhancing hair root function, etc., as active components, are being sold on the market. However, among them, products having appreciable effect do not exist yet, and side effects are raised in most of products.
As hair growth products, Minoxidil (U.S. Pat. No. 3,382,247) was initially developed and used for the purpose of promoting blood circulation, and then proved a hair growth effect as a side effect among patients using Minoxidil, and after that, received approval from the U.S. Food and Drug Administration (FDA) as raw material for hair growth. Even now, Minoxidil has been used as a therapeutic agent for hair growth. Finasteride (Merck, U.S. Pat. No. 5,215,894) was initially used as a prostate treatment for men, but has also been used as a therapeutic agent for male pattern alopecia by controlling a dose in a human body.
However, it has been reported that Minoxidil has side effects such as stickiness and skin irritation, and Finasteride which is orally administered at present has side effects such as sexual dysfunction, etc., depending on its intake, and is effective for hair loss only when being steadily taken. In addition, the effect may not be expected when applying 5 α-reductase activation inhibitors thereof, but be expected only when orally administrating 5 α-reductase activation inhibitors thereof, such that there are a lot of inconvenience in use.
In consideration of these above-described problems, the present inventors made an effort to provide a composition for external application which is useful for preventing hair loss and promoting hair growth by including a novel compound that prevents signs of skin damage and skin aging to stimulate hair growth factors, thereby producing a hair shaft, promoting hair growth, and delaying hair loss to have a hair growth effect.